--- /dev/null
+/*
+ * Copyright (C) 2016, Semihalf
+ * Author: Tomasz Nowicki <tn@semihalf.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * This file implements early detection/parsing of I/O mapping
+ * reported to OS through firmware via I/O Remapping Table (IORT)
+ * IORT document number: ARM DEN 0049A
+ */
+
+#define pr_fmt(fmt) "ACPI: IORT: " fmt
+
+#include <linux/acpi_iort.h>
+#include <linux/kernel.h>
+#include <linux/pci.h>
+
+typedef acpi_status (*iort_find_node_callback)
+ (struct acpi_iort_node *node, void *context);
+
+/* Root pointer to the mapped IORT table */
+static struct acpi_table_header *iort_table;
+
+static LIST_HEAD(iort_msi_chip_list);
+static DEFINE_SPINLOCK(iort_msi_chip_lock);
+
+static struct acpi_iort_node *iort_scan_node(enum acpi_iort_node_type type,
+ iort_find_node_callback callback,
+ void *context)
+{
+ struct acpi_iort_node *iort_node, *iort_end;
+ struct acpi_table_iort *iort;
+ int i;
+
+ if (!iort_table)
+ return NULL;
+
+ /* Get the first IORT node */
+ iort = (struct acpi_table_iort *)iort_table;
+ iort_node = ACPI_ADD_PTR(struct acpi_iort_node, iort,
+ iort->node_offset);
+ iort_end = ACPI_ADD_PTR(struct acpi_iort_node, iort_table,
+ iort_table->length);
+
+ for (i = 0; i < iort->node_count; i++) {
+ if (WARN_TAINT(iort_node >= iort_end, TAINT_FIRMWARE_WORKAROUND,
+ "IORT node pointer overflows, bad table!\n"))
+ return NULL;
+
+ if (iort_node->type == type &&
+ ACPI_SUCCESS(callback(iort_node, context)))
+ return iort_node;
+
+ iort_node = ACPI_ADD_PTR(struct acpi_iort_node, iort_node,
+ iort_node->length);
+ }
+
+ return NULL;
+}
+
+static acpi_status iort_match_node_callback(struct acpi_iort_node *node,
+ void *context)
+{
+ struct device *dev = context;
+ acpi_status status;
+
+ if (node->type == ACPI_IORT_NODE_NAMED_COMPONENT) {
+ struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER, NULL };
+ struct acpi_device *adev = to_acpi_device_node(dev->fwnode);
+ struct acpi_iort_named_component *ncomp;
+
+ if (!adev) {
+ status = AE_NOT_FOUND;
+ goto out;
+ }
+
+ status = acpi_get_name(adev->handle, ACPI_FULL_PATHNAME, &buf);
+ if (ACPI_FAILURE(status)) {
+ dev_warn(dev, "Can't get device full path name\n");
+ goto out;
+ }
+
+ ncomp = (struct acpi_iort_named_component *)node->node_data;
+ status = !strcmp(ncomp->device_name, buf.pointer) ?
+ AE_OK : AE_NOT_FOUND;
+ acpi_os_free(buf.pointer);
+ } else if (node->type == ACPI_IORT_NODE_PCI_ROOT_COMPLEX) {
+ struct acpi_iort_root_complex *pci_rc;
+ struct pci_bus *bus;
+
+ bus = to_pci_bus(dev);
+ pci_rc = (struct acpi_iort_root_complex *)node->node_data;
+
+ /*
+ * It is assumed that PCI segment numbers maps one-to-one
+ * with root complexes. Each segment number can represent only
+ * one root complex.
+ */
+ status = pci_rc->pci_segment_number == pci_domain_nr(bus) ?
+ AE_OK : AE_NOT_FOUND;
+ } else {
+ status = AE_NOT_FOUND;
+ }
+out:
+ return status;
+}
+
+static int iort_id_map(struct acpi_iort_id_mapping *map, u8 type, u32 rid_in,
+ u32 *rid_out)
+{
+ /* Single mapping does not care for input id */
+ if (map->flags & ACPI_IORT_ID_SINGLE_MAPPING) {
+ if (type == ACPI_IORT_NODE_NAMED_COMPONENT ||
+ type == ACPI_IORT_NODE_PCI_ROOT_COMPLEX) {
+ *rid_out = map->output_base;
+ return 0;
+ }
+
+ pr_warn(FW_BUG "[map %p] SINGLE MAPPING flag not allowed for node type %d, skipping ID map\n",
+ map, type);
+ return -ENXIO;
+ }
+
+ if (rid_in < map->input_base ||
+ (rid_in >= map->input_base + map->id_count))
+ return -ENXIO;
+
+ *rid_out = map->output_base + (rid_in - map->input_base);
+ return 0;
+}
+
+static struct acpi_iort_node *iort_node_map_rid(struct acpi_iort_node *node,
+ u32 rid_in, u32 *rid_out,
+ u8 type)
+{
+ u32 rid = rid_in;
+
+ /* Parse the ID mapping tree to find specified node type */
+ while (node) {
+ struct acpi_iort_id_mapping *map;
+ int i;
+
+ if (node->type == type) {
+ if (rid_out)
+ *rid_out = rid;
+ return node;
+ }
+
+ if (!node->mapping_offset || !node->mapping_count)
+ goto fail_map;
+
+ map = ACPI_ADD_PTR(struct acpi_iort_id_mapping, node,
+ node->mapping_offset);
+
+ /* Firmware bug! */
+ if (!map->output_reference) {
+ pr_err(FW_BUG "[node %p type %d] ID map has NULL parent reference\n",
+ node, node->type);
+ goto fail_map;
+ }
+
+ /* Do the RID translation */
+ for (i = 0; i < node->mapping_count; i++, map++) {
+ if (!iort_id_map(map, node->type, rid, &rid))
+ break;
+ }
+
+ if (i == node->mapping_count)
+ goto fail_map;
+
+ node = ACPI_ADD_PTR(struct acpi_iort_node, iort_table,
+ map->output_reference);
+ }
+
+fail_map:
+ /* Map input RID to output RID unchanged on mapping failure*/
+ if (rid_out)
+ *rid_out = rid_in;
+
+ return NULL;
+}
+
+static struct acpi_iort_node *iort_find_dev_node(struct device *dev)
+{
+ struct pci_bus *pbus;
+
+ if (!dev_is_pci(dev))
+ return iort_scan_node(ACPI_IORT_NODE_NAMED_COMPONENT,
+ iort_match_node_callback, dev);
+
+ /* Find a PCI root bus */
+ pbus = to_pci_dev(dev)->bus;
+ while (!pci_is_root_bus(pbus))
+ pbus = pbus->parent;
+
+ return iort_scan_node(ACPI_IORT_NODE_PCI_ROOT_COMPLEX,
+ iort_match_node_callback, &pbus->dev);
+}
+
+void __init acpi_iort_init(void)
+{
+ acpi_status status;
+
+ status = acpi_get_table(ACPI_SIG_IORT, 0, &iort_table);
+ if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
+ const char *msg = acpi_format_exception(status);
+ pr_err("Failed to get table, %s\n", msg);
+ }
+}
projects / platform / kernel / linux-rpi.git / commitdiff